Cell C no feedback after 50 calls

This is my number ***. My company changed ownership in June, So did my salary date. I phoned Cell C several times to let them know. For 3 month I paid penaltyfee. In June I paid in R450 and still took the whole amount the end of the month. I phone 50 times for them to refund me. Every time they ask me to send proof of payment. Every time they say it will take 2 working days for investigation and 7 days vir refund. So after 50 calls no feedback and no refund.